A gas turbine engine including a hard wall fan containment case made from aluminum alloy benefits from the use of an inner ballistic liner. The inner ballistic liner is made from a material with high shear strength, such as an aromatic fabric impregnated with an organic polymer. The inner ballistic liner mitigates an initial shear threat from a liberated fan blade, allowing the fan containment case to have a thinner wall and an optimized design weight. This configuration can be used when the fan blade is also made of an aluminum alloy. At high altitudes, fan temperatures are very cold, causing materials, such as aluminum alloy, with a high coefficient of expansion to contract. However, these temperatures have a minimal effect on materials with a low coefficient of expansion, such as an aramid fabric.